TomTom XXL540 not working with battery

Hi,
Recently I had the battery replaced on my TomTom XXL540 device. I placed the device on charge for 2 hours to allow new battery to be fully charged. I removed the charger and then pressed the power button down, my device failed to power up.

Connected the device to my computer, yes device powered up no problem.

I like to know what the problem is with my device as to why it cannot be powered up using its own battery supply.

I'm in Queensland, Australia and would like to get my device working properly as it should. Warranty has expired and yes it's an old device which is no longer supported. At the end of the day, I want the device fixed.

Hi,
I thought that might have been the issue regarding battery, the supplier of the replacement battery reckons its not faulty, The multimeter read 3.9v , don't know if it should be higher or not, I did leave the battery on charge for 2 hours. Battery had 3.7v written on the packet.

I don't know what a fully charged battery should read. I'm only assuming it was ok as the battery read 3.9v on the multimeter.

I did place one of my older batteries that came out of it, it might have been dead though.

That is the correct voltage but obviously it is not holding its charge which is why it runs only when plugged in. There is a small power integrated circuit (ic) which will blow mostly if it ever saw 12v instead of 5v so that may be the problem even with a brand new battery fitted.

The other TomTom device I have is identical to the one I'm trying to fix. I replaced a new battery in that one, it definitely holds its charge for a lengthy period when disconnected from the car or when being charged through its charger using mains power.

Either there is a fault somewhere in the motherboard connection where the battery plug sits or a dud battery. I assume the voltage regulator is working on it otherwise I would not be able to have the device power up. All seems to be bypassing the battery and every time I power it up I need to change the time clock.

I reopened my working TomTom XXL540 , removed the battery and plugged it into the other TomTom XXL540 which is causing issue. Yep, would not power up with the battery that I know is good. I even plugged in the other battery into my working TomTom and yes, battery is good.

From what I have discovered so far is that the other TomTom XXL540 device fails to power up from the battery. I removed the battery and it can still be powered up from the vehicle via devices USB voltage controlled plug and it can be powered up using mains charger specific for TomTomXXL540.

It's obviously a fault somewhere either in the motherboard. It would be great if these motherboards can be replaced instead of purchasing a new device.